/*
 *
 * Copyright 2015 gRPC authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#include <chrono>
#include <iostream>
#include <memory>
#include <random>
#include <string>
#include <thread>

#include <grpc/grpc.h>
#include <grpcpp/channel.h>
#include <grpcpp/client_context.h>
#include <grpcpp/create_channel.h>
#include <grpcpp/security/credentials.h>
#include "helper.h"
#ifdef BAZEL_BUILD
#include "examples/protos/route_guide.grpc.pb.h"
#else
#include "route_guide.grpc.pb.h"
#endif

using grpc::Channel;
using grpc::ClientContext;
using grpc::ClientReader;
using grpc::ClientReaderWriter;
using grpc::ClientWriter;
using grpc::Status;
using routeguide::Point;
using routeguide::Feature;
using routeguide::Rectangle;
using routeguide::RouteSummary;
using routeguide::RouteNote;
using routeguide::RouteGuide;

Point MakePoint(long latitude, long longitude) {
    Point p;
    p.set_latitude(latitude);
    p.set_longitude(longitude);
    return p;
}

Feature MakeFeature(const std::string& name,
                    long latitude, long longitude) {
    Feature f;
    f.set_name(name);
    f.mutable_location()->CopyFrom(MakePoint(latitude, longitude));
    return f;
}

RouteNote MakeRouteNote(const std::string& message,
                        long latitude, long longitude) {
    RouteNote n;
    n.set_message(message);
    n.mutable_location()->CopyFrom(MakePoint(latitude, longitude));
    return n;
}

class RouteGuideClient {
public:
    RouteGuideClient(std::shared_ptr<Channel> channel, const std::string& db)
            : stub_(RouteGuide::NewStub(channel)) {
        routeguide::ParseDb(db, &feature_list_);
    }

    void GetFeature() {
        Point point;
        Feature feature;
        point = MakePoint(409146138, -746188906);
        GetOneFeature(point, &feature);
        point = MakePoint(0, 0);
        GetOneFeature(point, &feature);
    }

    void ListFeatures() {
        routeguide::Rectangle rect;
        Feature feature;
        ClientContext context;

        rect.mutable_lo()->set_latitude(400000000);
        rect.mutable_lo()->set_longitude(-750000000);
        rect.mutable_hi()->set_latitude(420000000);
        rect.mutable_hi()->set_longitude(-730000000);
        std::cout << "Looking for features between 40, -75 and 42, -73"
                  << std::endl;

        std::unique_ptr<ClientReader<Feature> > reader(
                stub_->ListFeatures(&context, rect));
        while (reader->Read(&feature)) {
            std::cout << "Found feature called "
                      << feature.name() << " at "
                      << feature.location().latitude()/kCoordFactor_ << ", "
                      << feature.location().longitude()/kCoordFactor_ << std::endl;
        }
        Status status = reader->Finish();
        if (status.ok()) {
            std::cout << "ListFeatures rpc succeeded." << std::endl;
        } else {
            std::cout << "ListFeatures rpc failed." << std::endl;
        }
    }

    void RecordRoute() {
        Point point;
        RouteSummary stats;
        ClientContext context;
        const int kPoints = 10;
        unsigned seed = std::chrono::system_clock::now().time_since_epoch().count();

        std::default_random_engine generator(seed);
        std::uniform_int_distribution<int> feature_distribution(
                0, feature_list_.size() - 1);
        std::uniform_int_distribution<int> delay_distribution(
                500, 1500);

        std::unique_ptr<ClientWriter<Point> > writer(
                stub_->RecordRoute(&context, &stats));
        for (int i = 0; i < kPoints; i++) {
            const Feature& f = feature_list_[feature_distribution(generator)];
            std::cout << "Visiting point "
                      << f.location().latitude()/kCoordFactor_ << ", "
                      << f.location().longitude()/kCoordFactor_ << std::endl;
            if (!writer->Write(f.location())) {
                // Broken stream.
                break;
            }
            std::this_thread::sleep_for(std::chrono::milliseconds(
                    delay_distribution(generator)));
        }
        writer->WritesDone();
        Status status = writer->Finish();
        if (status.ok()) {
            std::cout << "Finished trip with " << stats.point_count() << " points\n"
                      << "Passed " << stats.feature_count() << " features\n"
                      << "Travelled " << stats.distance() << " meters\n"
                      << "It took " << stats.elapsed_time() << " seconds"
                      << std::endl;
        } else {
            std::cout << "RecordRoute rpc failed." << std::endl;
        }
    }

    void RouteChat() {
        ClientContext context;

        std::shared_ptr<ClientReaderWriter<RouteNote, RouteNote> > stream(
                stub_->RouteChat(&context));

        std::thread writer([stream]() {
            std::vector<RouteNote> notes{
                    MakeRouteNote("First message", 0, 0),
                    MakeRouteNote("Second message", 0, 1),
                    MakeRouteNote("Third message", 1, 0),
                    MakeRouteNote("Fourth message", 0, 0)};
            for (const RouteNote& note : notes) {
                std::cout << "Sending message " << note.message()
                          << " at " << note.location().latitude() << ", "
                          << note.location().longitude() << std::endl;
                stream->Write(note);
            }
            stream->WritesDone();
        });

        RouteNote server_note;
        while (stream->Read(&server_note)) {
            std::cout << "Got message " << server_note.message()
                      << " at " << server_note.location().latitude() << ", "
                      << server_note.location().longitude() << std::endl;
        }
        writer.join();
        Status status = stream->Finish();
        if (!status.ok()) {
            std::cout << "RouteChat rpc failed." << std::endl;
        }
    }

private:

    bool GetOneFeature(const Point& point, Feature* feature) {
        ClientContext context;
        Status status = stub_->GetFeature(&context, point, feature);
        if (!status.ok()) {
            std::cout << "GetFeature rpc failed." << std::endl;
            return false;
        }
        if (!feature->has_location()) {
            std::cout << "Server returns incomplete feature." << std::endl;
            return false;
        }
        if (feature->name().empty()) {
            std::cout << "Found no feature at "
                      << feature->location().latitude()/kCoordFactor_ << ", "
                      << feature->location().longitude()/kCoordFactor_ << std::endl;
        } else {
            std::cout << "Found feature called " << feature->name()  << " at "
                      << feature->location().latitude()/kCoordFactor_ << ", "
                      << feature->location().longitude()/kCoordFactor_ << std::endl;
        }
        return true;
    }

    const float kCoordFactor_ = 10000000.0;
    std::unique_ptr<RouteGuide::Stub> stub_;
    std::vector<Feature> feature_list_;
};

int main(int argc, char** argv) {
    // Expect only arg: --db_path=path/to/route_guide_db.json.
    std::string db = routeguide::GetDbFileContent(argc, argv);
    RouteGuideClient guide(
            grpc::CreateChannel("localhost:50051",
                                grpc::InsecureChannelCredentials()),
            db);

    std::cout << "-------------- GetFeature --------------" << std::endl;
    guide.GetFeature();
    std::cout << "-------------- ListFeatures --------------" << std::endl;
    guide.ListFeatures();
    std::cout << "-------------- RecordRoute --------------" << std::endl;
    guide.RecordRoute();
    std::cout << "-------------- RouteChat --------------" << std::endl;
    guide.RouteChat();

    return 0;
}